1. Technical Field
The technology disclosed herein relates to a lens barrel. More specifically, the technology disclosed herein relates to a lens barrel used in a digital camera or the like.
2. Background Information
Recent years have witnessed the growing popularity of digital cameras that make use of imaging element such as a Charge Coupled Device (CCD), Complementary Metal Oxide Semiconductor (CMOS) sensor, and the like and convert an optical image into an electrical signal, and digitize and record the electrical signal.
With such a digital camera, not only is a higher pixel count needed for the CCD or CMOS sensor, but higher performance is needed for the lens barrel that forms an optical image on the imaging element. More specifically, there is a need for a high-performance lens barrel with which a higher-magnification zoom lens system can be installed and image blurring during imaging can be corrected. Furthermore, there is a need for a lens barrel which can take higher-quality moving images. For example, there is a need for a lens barrel with which quiet, extended-time imaging is possible, that is, a lens barrel that has quietness and also has low power consumption.
Meanwhile, there is a need to reduce the overall size of the product to make it more easily portable. The lens barrel is considered to contribute greatly to reducing the overall size of the product, so various proposals have been made for making a lens barrel more compact.
With the lens barrel discussed in Japanese Patent Application 2008-46504, blur correction is accomplished by moving the imaging element unit with the actuator in a direction perpendicular to the optical axis. This type of blur correction is called a sensor shift method.
However, when a sensor shift type of blur correction is used, there is the risk that the actuator will get bigger than the actuator of an optical system that performs blur correction by moving a correcting lens. For example, the imaging element weighs approximately three times as much as a correcting lens. Also, the imaging element requires numerous signal lines, so these signal lines must bend while the element is driven. In particular, digital cameras that make use of CMOS image sensors to improve sequential imaging performance have become more popular in recent years. The number of circuit wires connected to a CMOS image sensor is greater than that with a CCD image sensor, so the drive load ends up being higher. For example, when an imaging element is driven, at least about five times the energy is required than when a correcting lens is driven.
As discussed above, with sensor shift blur correction, the actuator ends up being bulkier. Accordingly, it is known that there is a limit to how compact a lens barrel can be made with sensor shift blur correction.